A U.S. Chinook helicopter crashed yesterday in the mountains of southern Afghanistan, killing all five crew members, the U.S. military said. The aircraft did not appear to have been shot down, officials said.

The CH-47 chopper was returning to base while supporting operations in southern Zabul province, about 180 miles southwest of Kabul, when it went down, sources said. U.S. ground forces had reached the crash scene and were providing security for recovery operations.

“There is no indication at this time that this is a result of hostile fire,” said military spokesman Lt. Col. Jerry O’Hara said. “There are no survivors.”

An Afghan spokesman said there was no fighting in the Zabul area, scene of fierce fighting with a resurgent Taliban, at the time of the crash and that the craft was returning to base after dropping off troops for a raid on a suspected target.

The deaths bring to 195 the number of U.S. military service members killed in and around Afghanistan since U.S.-led forces ousted the Taliban in late 2001.

With elections taking place last week, but results not being finalized until next week, there has been an upsurge in violence in Afghanistan which has claimed 1,300 lives since March – and 79 of the 195 U.S. deaths.

The crash is the third this year involving the large troop-carrying Chinook, used in remote inaccessible parts of Afghanistan. With a combined 36 deaths, the crashes have contributed to what already is the deadliest year for America in the Afghanistan operation.